The present invention relates to key telephone systems and more particularly to a telephone having built-in test capability for use in such a system. The telephone of the present invention includes a microprocessor which can be placed into a test mode for verifying the proper operation of the components of the telephone.
Key telephone systems generally comprise a plurality of telephone stations (referred to herein as "telephones") and a central key service unit ("KSU") which interconnects the telephones with each other and to outside telephone trunk lines. The KSU provides control functions for the key telephone system and establishes communication paths between telephones. When outside calls are involved, the KSU establishes communication paths between telephones and telephone trunk lines.
Each telephone in a key telephone system must be connected to the KSU in order to function. Such telephones would not operate if plugged directly into a telephone line. An example of a key telephone system with which such phones are used is provided in commonly assigned co-pending U.S. patent application Ser. No. 616,566 filed May 31, 1984, entitled "Key Telephone System", pertinent portions of which are incorporated herein by reference.
In past key telephone systems, telephones which were believed to be in need for repair were disconnected from the system and returned to a central repair facility which would determine if the telephone was, in fact, broken. Many times, telephones returned to the central repair facility were fine, the problem being at the KSU end of the system from which the telephone came. Also, in manufacturing such telephones an expensive test jig is necessary to verify proper operation of the telephone after assembly thereof. A similar test jig is required by field repairmen to verify proper operation of the telephones in the field. The lack of a convenient means to test telephones, and the inability of a telephone owner and/or user to test his own phone has been a tremendous disadvantage in maintaining the reliability and overall performance of key telephone systems.
It would be advantageous to provide telephones for a key telephone system wherein each telephone has a built-in testing capability. Such capability should be easy to access by a designated user or users of the key telephone system. Once accessed, it should be easy to perform the tests provided to determine whether the components of the telephone are operating properly. Components which would be advantageous to test include the indicator lamps on the telephone, the telephone key pad, all other switches on the telephone, the telephone earphone and microphone, and, if provided, the handsfree speaker and hands-free microphone of the telephone. It would be further advantageous to provide a test for measuring the noise characteristics of the telephone audio circuitry.
The present invention provides such a telephone. A microprocessor within the telephone can be placed into a test mode of operation, during which a plurality of tests can be stepped through and conducted on the telephone to determine if components of the telephone are operating properly.